Apparatus for causing delayed operation of electroresponsive devices



Jan. 10, 1939. M R N R 2,143,501

APPARATUS FOR CAUSING DELAYED OPERATION OF ELECTRORESPONSIVE DEVICES Filed Oct. 21, 1936 IN ENII'OR D [Wally ngde BY 12 HIS ATTORNEY Parmesan. 10, 1939 UNITED STATE APPARATUS FOR CAUSING DELAYED OPER- ATION F ELECTRORESPONSIVE DE- VICES Mills R. Snyder, Norfolk, Va., assignor toThe Union Switch &' Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application October 21, 1Si36, Serial No. 106,8 54

1 Claim.

My invention relates to. apparatus for causing delayed operation of electro-responsive devices such as relays, for example. Apparatus embodying my invention is well adapted for providing 5 delayed operation of relays in railway signaling circuits, especially where a substantial time delay period is required, although my invention is not limited to such circuits.

.1 will describe one form of apparatus embody-.

CR. closes a pickup circuit for the time delayrelay DR which latter relay is deenergized prior to the time relay CR is operated, so that its back contact 3-4 is closed. Thepickup of relay 25 DH is controlled by a vacuum tube VT having a heater H and a cathode C which requires an appreciable time for reaching its operating temperature. closes, a circuit is completed for the heater H, which circuit may be traced from one terminal of battery B, wires 6 and I, back contact 3-4 of relay DR, wire 8, heater H, wires 9 and iii, and contact 2 of relay CR, to the other terminal of battery B.-

At the same time, a circuit is prepared for energizing relay DR. This circuit extends from one terminal of battery B, wires 6 and i4, cathode C, plate P, wires H and i 2, winding of relay DR, wires l3 and i0, and contact 2, to the other terminal of battery B. The voltage of battery B is so chosen with respect to the type of vacuum tube which is used that the required time will elapse before the cathode C reaches the proper .temperature for permitting suiliclent current to 5 pass to the plate P for picking up,,relay DR.

After the lapse of a predetermined time interval following the closing of contact 2 of relay CR, relay DR will pick up and in so doing will open its back contact 3-4 and close its front 50 contact 3-5. Any suitable control apparatus (not shown) can now be operated over the front contact I 5 of relay DR. The opening of back contact 3--'-4 interrupts the heater circuit and permits the cathode C to cool, in preparation for 55 a subsequent time delay operation.' The flow of current to relay DR is, however, not interrupted during the transfer time of contact finger 3 because the temperature of cathode C is maintained for a short time interval following the a tube having only'the usual vmay be used, if desired.- By suitably propor- As soon as contact 2 of relay CR- whereby a pick-up circuit is provided for said 'opening of the heater circuit. The closing of front contact 3-5 establishes'a holding circuit for relay DR, which circuit is directly energized from the battery B and excludes the vacuum tube VT. From this point on, relay DR will 5 remain energized as long .as relay CR remains in its picked upcon'd ition. When relay CR is released, relay DR will also release and-cannot be picked up again until after contact 2 is closed and the vacuum tube VT goes through its previously described heating cycle.

The vacuum tube VT may be of any suitable type but is preferably a high vacuum or hard" rectifying tube.-'Uslng a standard commercial type of rectifying tube, I have obtained pickup times up to 10 seconds in duration for a 500 ohm line relay, and an 8.5 volt battery.

Although I have illustrated a fourelement vacuum tube, it is obvious that tubes having a different number of elements can be used. For example, a single-anode tube or v a two-element cathode and an anode tioning the parts, delay times either shorter or longer than, the 10 second interval referred to above may be obtained.

Although I have herein shown and described but one form of apparatus embodying my invention, it is understoodthat various changes and modifications may be made therein within the scope of the appended claim without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: I I

In combination, a relay having a contact finger with a front contact and a back contact cooperating therewith, a thermionic valve having a cathode, an anode, and a heater electrode, a single source of current for energizing both said relay and said thermionic. valve, a first connection from the negative terminal of said source to said contact finger, a heating circuit for said heater electrode including said source, said first connection, said contact finger. and said back 45 contact, a connection from said cathode to the negative terminal of said source, a connection from said anode through the winding of said relay to the positive terminal of said source relay including the cathode-to-anode path of said thermionic valve, and a holding circuit for said relay including said source, said first connection, said contact finger, and said front contact for maintaining said relay energized independently of said cathode-to-anode path following .a pick-up operation of said relay.

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